Oh My, Why Has My Basil Plant Turned Bitter?

You’ve worked hard to keep your basil plant growin’. Maybe you even started it from seed. That aromatic little herb has already yielded some pretty tasty leaves, so you expect no different from your next harvest. Only your latest homemade pesto tastes downright bitter. Bleh. What happened to your fresh, sweet basil? A number of factors can cause that tart taste, but it all comes down to care.